I have contacted several Welsh geneaologists and they agree that Linthicum, or the variants, are not Welsh. For one thing the name would be Cumlinth or in that form. If you wish to check this go to http://www.familysearch.org/Eng/Search/frameset_search.asphttp://www.familysearch.org/Eng/Search/frameset_search.asp and look up Linthicum/Linscomb (Thomas' first spelling), Lincicomb, the second spelling. There will be many entries for Thomas born in Wales in 1640 but without a parish registry for identification of location. These entries have been added after the fact by those who want to make certain their ancestor (Thomas) is in the IGI registry. The specific statement, which I have seen in a Maryland Historical Society document, was "He said he was a gentleman from Wales."